Names & FormulasNames & Formulas

(Nomenclature)(Nomenclature)

Anatomy of a Chemical Formula Anatomy of a Chemical Formula

AlAl22SOSO44

Numbers at the bottom are called Numbers at the bottom are called subscripts.subscripts.

They tell They tell how many atomshow many atoms of one type are in a of one type are in a compound.compound.

CaCa+2+2

Numbers at the top are called Numbers at the top are called superscriptssuperscripts. .

They tell you the They tell you the chargecharge of the atom. of the atom.

Polyatomic IonsPolyatomic Ions

Group of atoms that have an overall charge. Group of atoms that have an overall charge. You will find both subscripts and superscripts You will find both subscripts and superscripts in polyatomic ions.in polyatomic ions.

COCO33-2-2 carbon = 1

oxygen = 3

overall charge = -2

3 Categories of Compounds3 Categories of Compounds

1.1. IonicIonic

2.2. Acids & BasesAcids & Bases

3.3. MolecularMolecular

1) 1) Ionic CompoundsIonic CompoundsContain IONIC bonds.Contain IONIC bonds.Formed between Formed between metalsmetals and and non-metalsnon-metals..Ions combine in small, Ions combine in small, whole number ratios.whole number ratios.The sum of oxidation The sum of oxidation numbers will be zero! (they numbers will be zero! (they are neutral)are neutral)

Binary Ionic CompoundsBinary Ionic Compounds

All contain All contain twotwo elements.elements.

All end in All end in “ide”“ide”..

Binary Ionic CompoundsBinary Ionic Compounds

To write formula:To write formula:

1)1) Write Write ++ and and - - ions.ions.

2)2) Reduce oxidation numbersReduce oxidation numbers, , if possible.if possible.

3)3) “Criss-Cross”“Criss-Cross” number only number only to become subscript for to become subscript for other ion.other ion.

Examples…Examples…

sodium chloridesodium chloride

magnesium nitridemagnesium nitride

calcium oxidecalcium oxide

NaCl

Mg3N2

CaO

Binary Ionic CompoundsBinary Ionic Compounds

To Name:To Name:

1)1) CationsCations (+) retain the name (+) retain the name of the element.of the element.

2)2) AnionsAnions (-) keep the root (-) keep the root name but add name but add “ide”“ide” ending. ending.

Examples…Examples…

LiFLiFLithium fluorideLithium fluoride

SrClSrCl22Strontium chlorideStrontium chloride

AlAl22OO33

Aluminum oxideAluminum oxide

Multi-Charge MetalsMulti-Charge Metals

Most of the Most of the transition metals transition metals (and lead and tin)(and lead and tin) have have variable oxidation numbersvariable oxidation numbers. .

(they can have more than one)(they can have more than one)

Roman numerals are used Roman numerals are used to indicate charges for these to indicate charges for these elements.elements.Roman numerals always Roman numerals always belong to the metal.belong to the metal.(are always positive)(are always positive)

IMPORTANT EXCEPTIONS!IMPORTANT EXCEPTIONS!

Silver always forms a 1+ ion.Silver always forms a 1+ ion.

Zinc always forms a 2+ ion.Zinc always forms a 2+ ion.

Cadmium always forms a Cadmium always forms a

2+ ion.2+ ion.

Examples…Examples…

Iron (II) oxideIron (II) oxide

iron(III) oxideiron(III) oxide

chromium (IV) sulfidechromium (IV) sulfide

FeO

Fe2O3

CrS2

Examples…Examples…

CuOCuOCopper (II) oxideCopper (II) oxide

CrCr22SeSe33

chromium (III) selenidechromium (III) selenide

PbSPbS22

Lead (IV) sulfideLead (IV) sulfide

Ternary Ionic CompoundsTernary Ionic CompoundsContain 3 or more Contain 3 or more elements. (not binary)elements. (not binary)

Contain at least oneContain at least onePolyatomic Ion.Polyatomic Ion.

(look on the back of your P.T.)(look on the back of your P.T.)

Polyatomic IonsPolyatomic Ions

All P.A.I. contain at least All P.A.I. contain at least two different elements.two different elements.

Example:Example:

Chlorate Chlorate ClO ClO33-1-1

(Contains chlorine and oxygen)(Contains chlorine and oxygen)

To name/write formulas:To name/write formulas:

Use the same rules as Use the same rules as binary ionic compounds.binary ionic compounds.

Enclose P.A.I. in Enclose P.A.I. in parenthesis when parenthesis when necessary.necessary.

Examples…..Examples…..

Aluminum phosphateAluminum phosphate

AlPOAlPO44

Sodium sulfateSodium sulfate

NaNa22SOSO44

Iron (II) bromateIron (II) bromate

Fe(BrOFe(BrO33))22

Examples…Examples…CaCOCaCO33

Calcium carbonateCalcium carbonate

Cu(NOCu(NO33))22

Copper (II) nitrateCopper (II) nitrate

(NH(NH44))33NN

Ammonium nitrideAmmonium nitride

Naming Naming

Acids & BasesAcids & Bases

2)2) Acids and BasesAcids and Bases::

All traditional acids begin All traditional acids begin with Hydrogen (H).with Hydrogen (H).

All traditional bases end All traditional bases end with Hydroxide (OH).with Hydroxide (OH).

Acids are easy to recognize Acids are easy to recognize because they begin with “H”. because they begin with “H”.

Bases are easy to recognize Bases are easy to recognize because they end with “OH”.because they end with “OH”.

BasesBasesThere are no special rules There are no special rules for naming bases! (they are for naming bases! (they are ionic)ionic)

EX: NaOHEX: NaOHSodium hydroxideSodium hydroxide

Binary AcidsBinary Acids

Have only two elements.Have only two elements.

(hydrogen and a non-(hydrogen and a non-metal from the Periodic metal from the Periodic Table)Table)

To Name:To Name:

1)1)Use the prefix “hydro”.Use the prefix “hydro”.

2) Add the suffix “ic”.2) Add the suffix “ic”.Examples:Examples:

HHClCl

HH33NN

hydrohydrochlorchloric acidic acid

hydrohydronitrnitric acidic acid

To write formulas:To write formulas:

1)1) Start with HStart with H+1+1

2)2) End with negative End with negative

(non-metal) ion from (non-metal) ion from

periodic table.periodic table.

3)3) “Criss-Cross”.“Criss-Cross”.

Examples:Examples:

Hydroiodic acid Hydroiodic acid

Hydrophosphoric acidHydrophosphoric acid

HI

H3P

Ternary AcidsTernary Acids

Have at least three Have at least three elements: elements:

(H and a polyatomic ion)(H and a polyatomic ion)

To Name:To Name:

1) 1) Use NO “hydro” prefix!Use NO “hydro” prefix!

2) Add suffix:2) Add suffix:

if “ate” ion, “ic” suffixif “ate” ion, “ic” suffix

if “ite” ion, “ous” suffix if “ite” ion, “ous” suffix

Examples…Examples…

HClOHClO33

HH22SOSO33

chloric acidchloric acid

sulfous acid

To write formula:To write formula:

1)1) Start with HStart with H+1+1

2)2) End with negative End with negative

(polyatomic) ion.(polyatomic) ion.

3)3) “Criss-Cross”.“Criss-Cross”.

Examples:Examples:

perchloric acidperchloric acid

chlorous acidchlorous acid

HClO4

HClO2

3)3) MolecularMolecular::

Used to name Used to name CovalentlyCovalently bonded atoms.bonded atoms.

Made up of Made up of non-metalsnon-metals only.only.

Molecular Molecular CompoundsCompounds

Contain Contain COVALENTCOVALENT bonds. bonds.

The same elements can The same elements can combine in various ways.combine in various ways.

PrefixesPrefixes are used to tell the are used to tell the difference between them.difference between them.

We will only learn We will only learn BINARYBINARY molecular compounds.molecular compounds.

BinaryBinary = only contains two = only contains two different elements.different elements.

All binary compounds end All binary compounds end in in “ide”“ide”..

Prefixes:Prefixes:

1 = mono1 = mono 6 = hexa6 = hexa

2 = di2 = di 7 = hepta7 = hepta

3 = tri3 = tri 8 = octa8 = octa

4 = tetra4 = tetra 9 = nona9 = nona

5 = penta5 = penta 10 = deca10 = deca

To name:To name:

Use prefixes on first atom, Use prefixes on first atom, except for “mono”.except for “mono”.

Always use prefixes on Always use prefixes on the last atom.the last atom.

Change ending to “ide”.Change ending to “ide”.

Examples…Examples…

SS22OO33

COCO

OFOF22

disulfur trioxide

carbon monoxide

oxygen difluoride

To write formulas:To write formulas:

Look at prefixes Look at prefixes attached to each attached to each element to determine element to determine subscript.subscript.

Examples…Examples…

Arsenic pentiodideArsenic pentiodide

Carbon ditellurideCarbon ditelluride

Diphosphorus trioxideDiphosphorus trioxide

AsI5

CTe2

P2O3